The present invention pertains to mounting arrangements for electronic semi-conductor devices and in particular to a novel arrangement for mounting semi-conductor devices in pairs in a control panel to effect electrical connection of each semi-conductor device with an electrical terminal fixedly mounted on the panel.
Currently available electronic semi-conductor devices are packaged in various ways. In one such package the semi-conductor structure is contained within a housing shaped in the form of a circular disc. The ends of the disc are flat circular surfaces which form the principal external electrical terminals for the semi-conductor device. Other terminals in the form of small wire leads may emanate from the device for the purpose of conducting a triggering signal to the semi-conductor to initiate conduction thereof with main current flow being through the device between the flat circular end surfaces thereof. Generally, semi-conductor devices of this type carry an appreciable amount of current. There are presently various possible ways of mounting such devices in order to effect electrical connection to the flat circular end terminal surfaces thereof. One way is by clamping the device between a pair of conductor plates thereby promoting good surface contact between each plate and the corresponding end surface of the device whereby ohmic losses at the mating surfaces are minimized and heat transfer from the device to the conducting plates is promoted. While this mounting arrangement may be acceptable where a single semi-conductor device is to be mounted; it has been observed that satisfactory contact between conductor plates and semi-conductor devices cannot always necessarily be obtained when a number of semi-conductor devices and plates are stacked together and clamped. Illustrative arrangements for mounting semi-conductor devices are shown in prior U.S. Pat. Nos. 2,781,480, 3,333,163, 3,356,914 and 3,447,118.
The present invention is directed toward a novel mounting arrangement for electronic semi-conductor devices in which an improved surface contact between semi-conductor devices and conductor plates is obtained where a plurality of semi-conductors and plates are to be stacked together. Accordingly, the present invention yields a mounting arrangement having improved thermal and electrical conductivity between the semi-conductor devices and mounting plates thereby minimizing ohmic losses and better protecting the semi-conductor device from potentially damaging thermal build-up. This improvement is particularly important for solid state devices having large current ratings although the invention also is useful with devices having lesser ratings.
The present invention also provides an improved mounting arrangement wherein a number of semi-conductor devices are to be stacked together each between a pair of plates and the stack attached to fixed terminals mounted on a control cabinet. In an installation of this type, the present invention compensates for a certain mount of misalignment between the terminals so as to permit a good electrical contact to be made between the terminals and the plates of the stack while at the same time maintaining good contact between the semi-conductor devices and the plates. Moreover, the invention possesses economy and facility in construction and assembly.
The foregoing features and advantages, as well as additional ones, will be seen in the ensuing description and claims which are to be taken in conjunction with the accompanying drawings. The drawings illustrate a preferred embodiment according to the best mode presently contemplated in carrying out the invention.